TPS5420: Suggested layout in data sheet is different than the demo bard

Bob LaFrance

Part Number: TPS5420
Other Parts Discussed in Thread: TPS5410

The TPS5420 datasheet shows a layout on page. In this layout the input capacitor is on one side of the chip while the output inductor and output capacitor is opposite. This puts the controller inside the current loop

The layout in the TPS5410EVM demo board is very different. it is a much tighter layout and doe not surround the controller.

My pcb designer just laid out board to data sheet. Is this a good layout or should I go to layout on demo board?

This is not a total apple to apple comparison. One part is a TPS5410 while the other is a TPS5420. I don't expect this should be a factor in the robustness of the layout.

thank you,

Bob

over 7 years ago

0 JohnTucker over 7 years ago

TI__Guru**** 191445 points

Both of those layout options are valid. I think the the layout used for TPS5410 does give slightly tighter circulating current loops and could be slightly better.

0 Bob LaFrance over 7 years ago in reply to JohnTucker

Prodigy 170 points

Hi John.

I am more concerned with the controller being splashed with noise being in the center of the loop. Is this a valid concern?

0 JohnTucker over 7 years ago in reply to Bob LaFrance

TI__Guru**** 191445 points

No not really. There are two circulating current paths. One on the input side thru the input capacitor to the IC VIN and GND pins. One on the output side from the PH node to Lout, Cout and back thru GND and the catch diode. The goal is to make those two loops a s tight as is prqactical. With these devices, there are a couple different valid approaches to this.

0 Bob LaFrance over 7 years ago in reply to JohnTucker

Prodigy 170 points

Got it. Thank you.

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TPS5420: Suggested layout in data sheet is different than the demo bard